1. Field of Use
The present invention relates to data processing apparatus and, more particularly, to apparatus for initializing a system to a predetermined state.
2. Prior Art
Certain prior art multiprocessing systems include a peer processor which operates under the control of a proprietary operating system and another peer processor which operates under the control of a nonproprietary operating system such as a UNIX.TM. operating system. An example of this type of system is described in U.S Pat. No. 4,992,930. FNT .TM. UNIX is a registered trademark of Unix System Laboratories, Inc.
In the above multiprocessor system, the nonproprietary peer processor was placed in an idle state while the remainder of the system, under the control of the proprietary peer processor, performed internal testing operations following the successful completion of which the system loaded the proprietary operating system. Thereafter, the nonproprietary peer processor was tested, loaded with a boot program and then its operating system.
The above arrangement was quite time-consuming and also required that the entire multiprocessor system be reset in order to verify the operability of the nonproprietary peer processor. Additionally, the nonproprietary peer processor was constructed from an Intel 80386 microprocessor chip and did not contain the extensive functionality of newer microprocessor chips and therefore did not require the same level of overall testing.
In systems which contain a board having a commodity processor and its own memory, a boot memory is used for storing BIOS which is the first code executed when the processor is reset or initialized. Normally, such memories are constructed from PROMs which can only be changed by replacing the PROM chips. Therefore, if the board was installed as part of a multiprocessor system, additional apparatus would be required for performing diagnostic testing before booting took place. Also, facilities would have to be provided for loading the diagnostic test routines in some way into the board's memory.
Accordingly, it is primary object of the present invention to provide a system which enables a processing unit to perform diagnostic testing and boot up its operating system.